He describes one of the more credible climate skeptics, Richard Muller, a physicist and researcher at the University of California-Berkeley, who recently concluded that climate change is real, after conducting his own study. According to Litz, climate scientists were especially pleased at this reversal since Muller’s study confirming climate change was funded by the Koch brothers, the Oklahoma oil barons who have “poured money into candidates and organizations that will fight to maintain our addiction to the oil they sell.” The Koch brothers are behind the right-wing Americans for Progress, a group that has actively tried to undermine the Northeast Regional Greenhouse Gas Initiative—a program of 10 Northeastern states to reduce global warming pollution from power plants.

Litz says:

All sides of the political discussion about what action to take on energy and climate change bear some responsibility for politicizing the science. We keep looking to science to provide the absolute certainty that science will never provide. Scientists are not and should not be in the business of making the political case for action.

The Intergovernmental Panel on Climate Change–a joint body of the United Nations and the World Meteorological Organization–has issued 4 comprehensive assessment reports on the state of climate change science since 1990. Its most recent assessment, issued in 2007, concluded that the warming of the climate is “unequivocal”—in other words, absolutely certain. In the same 2007 report, the intergovernmental body concluded it is “very likely” that humans are causing the warming. In IPCC parlance, “very likely” means that there is a greater than 90% chance that humans are causing the warming.

These are dramatic confidence levels on the two key issues in climate change. To the question of whether global warming is happening, the answer is “Yes, we are absolutely certain.” To the question, are humans causing global warming, the answer is “Yes, we are 90% sure they are.”

We’ve pushed the science far enough. We will never be absolutely certain about climate change. Waiting for certainty to act is irresponsible. The risks of inaction are too great.

Instead of waiting for more certainty on the science, we need our leaders at every level of government—local, state and national—to drive bold changes in the way we fuel our economy.